Improving eel stocks in Lake Bolmen

Lake Bolmen, a freshwater lake covering 184km², comprises a large part of Skåne, the southernmost part of Sweden. While the number of eel in Bolmen have increased in recent years, stock levels are much lower than expected and in a downward trend. Based on the number of fry released each year, experts estimate that the lake should produce between 35 and 40 tonnes of eel, yet, observed stocks have been significantly lower with only four tonnes of eel being produced annually in recent years. The cause of this reduced production is unclear and could be related to multiple factors.

To investigate the situation, the project Ålen i Bolmen (Eel in Lake Bolmen) has been created through a collaboration between the Lake Bolmen Fisheries Conservation Area Association and the Swedish University of Agricultural Sciences. The project aims to increase eel stocks by analysing underlying ecological factors and experimenting with new methods of releasing fry. Firstly, the project will investigate fry release sites. Secondly, the project will test releasing fry at different ages and sizes. One potential cause of high fry mortality rates in Bolmen could be related to a series of power plants situated on the lake. As such, fry of a certain size may be able to better navigate the lakes power plants, reducing mortality rates and allowing the fry to reach maturity.

In the medium-term, the project aims to provide ecological recommendations for the management of eel stocks in Bolmen, and other lakes with similar stock issues. Long-term the project aims to bring eel production in Bolmen back up to expected levels, which will be of significant economic benefit for commercial fishers. Furthermore, the processing and tourism sectors will also receive an increased income, benefiting the Halland FLAG territory as a whole and aligning with the FLAGs objective of developing tourism in the area.